.NET Framework April 2022 Security and Quality Rollup Updates

We are releasing the April 2022 Security and Quality Rollup Updates for .NET Framework.

Security

CVE-2022-26832 – .NET Framework Denial of Service

This security update addresses an issue where an unauthenticated attacker could cause a denial of service on an affected system.

• CVE-2022-26832

Quality and Reliability

This release contains the following quality and reliability improvements.

NET Libraries

• Addresses an issue when Ssl negotiation can hang indefinitely when client certificates are used when TLS 1.3 is negotiated. Before the change renegotiation (PostHandshakeAuthentiction) would fail and SslStream or HttpWebRequest would observe a timeout.

Winforms

• Addresses a leak of IRawElementProviderSimple objects which was introduced in .NET Framework 4.8. This is an opt-in fix, add the following compatibility switch to the app.config file in order to dispose the accessible objects:

        <runtime>
            <!-- AppContextSwitchOverrides values are in the form of 'key1=true|false;key2=true|false  -->
            <AppContextSwitchOverrides value="Switch.System.Windows.Forms.DisconnectUiaProvidersOnWmDestroy=true"/>
        </runtime>

Note: that when the accessibility server application opts into this fix, the accessibility client will receive errors when accessing the disconnected provider. This is expected because the corresponding control window is destroyed. Previous behavior where the provider was returning information for destroyed controls was incorrect.

Getting the Update

The Security and Quality Rollup is available via Windows Update, Windows Server Update Services, and Microsoft Update Catalog. The Security Only Update is available via Windows Server Update Services and Microsoft Update Catalog.

Microsoft Update Catalog

You can get the update via the Microsoft Update Catalog. For Windows 10, NET Framework 4.8 updates are available via Windows Update, Windows Server Update Services, Microsoft Update Catalog. Updates for other versions of .NET Framework are part of the Windows 10 Monthly Cumulative Update.

Note: Customers that rely on Windows Update and Windows Server Update Services will automatically receive the .NET Framework version-specific updates. Advanced system administrators can also take use of the below direct Microsoft Update Catalog download links to .NET Framework-specific updates. Before applying these updates, please ensure that you carefully review the .NET Framework version applicability, to ensure that you only install updates on systems where they apply.

The following table is for Windows 10 and Windows Server 2016+ versions.

The following table is for earlier Windows and Windows Server versions.

Previous Monthly Rollups

The last few .NET Framework Monthly updates are listed below for your convenience:

• .NET Framework February 2022 Cumulative Update Preview
• .NET Framework February 2022 Security and Quality Rollup
• .NET Framework January 2022 Cumulative Update Preview
• .NET Framework January 2022 Security and Quality Rollup Updates